I. Field of the Invention
This invention relates to document handling apparatus, particularly for use in copying machines. More particularly, the invention is concerned with such apparatus including a belt by which documents are engaged and conveyed and a belt hitch for supporting the belt.
II. Description of the Prior Art
Document handlers are used in photocopiers to feed a document to be copied, usually from a stack of such documents, to an exposure platen where it is registered. The document is held in position on the platen until the required number of copies have been made, and then moved to an output collection point for subsequent removal, e.g., by the machine operator. As the document is moved off the platen, another document may be fed from the stack into position for copying, and so on. The document handling apparatus should provide a convenient and reliable means of maximizing the copying capacity of the copier as well as improving the efficiency of the copier.
In such document handlers the document is conveniently conveyed over the platen by means of a belt, usually endless, which engages the document and slides it across the platen which is generally of glass. Once the document has been registered on the platen, the belt should slip on the surface of the document sandwiched between it and the platen. We have found that improved document handling may be achieved by reducing the contact area of the belt with the document. For this purpose we have proposed in our copending Application Ser. No. 687,062, filed May 17, 1976 and assigned to the same assignee as the present invention that a hitch be provided in the belt to support it out of contact with the document between document engaging zones adjacent the input and output ends of the platen.
The belt is conveniently provided in a platen cover which may be retracted to provide access to the platen, e.g., for manual insertion and removal of documents. Thus, another advantage of a belt hitch as proposed above is to support the belt and prevent it from sagging when the platen cover is lifted away from the platen.